Spliced veneer sheet offbearing mechanism



Aug. 25, 1953 A. c. CARLSON 2,649,976

SPLICED VENEER SHEET OFFBEARING MECHANISM Filed May 6, 1950 4 Sheets-Sheet 1 IN VEN TOR.

BY 3 z A rrolelvErs ARTHUR C 0421. sou

1953 A. c. CARLSON 2,649,976

SPLICED VENEER SHEET OFFBEARING MECHANISM Filed May 6, 1950 4 Sheets-Sheet 2 Q Q INVENTOR.

ARTHUR C CARLSOA/ A r TORNEYS Aug. 25, 1953 c, CARLSQN 2,649,976

SPLICED VENEER SHEET OFFBEARING MECHANISM Filed May 6, 1950 4 Sheets-Sheet 3 INVENTOR. ARTHUR C (A21. so-

A 7- TOENE Y5 7 1953 A. c. CARLSON 2,649,976

SPLICED VENEER SHEET OFFBEARING MECHANISM Filed May 6, 1950 4 Sheets-Sheet 4 J 1i T :QTL I "7" a INVENTOR.

ARTHUR C. CARLsoA/ A T T'ORNEYS Patented Aug. 25, 1953 SPLICED VENEER SHEET FFBEARING- MECHANISM Arthur C. Carlson, Anacortes, Wash, assignor,

by mesne assignments, to American Manufacturing Company, Inc;, Tacoma, Wash., a; corporation of Washington Application May 6, 1950, Serial No. 160,538

In my Patent No. 2,544,133, issued March 6, 1951, is disclosed a process and a mechanism for the edge-gluing or splicing of wood veneer strips into a continuous web of indefinite length.

This process is characterized by the bowing of the strips upwardly at their centers and in the directionof their lengths and of their grain, hence transverse to the resultant web, while they are passing through the glue-setting station, the bowing being progressive leading to that station. Most wood veneer is employed in the manufacture of plywood panels of standard sizes, and continuous webs heretofore formed by edgegluing while the strips are flat can readily be subdivided or clipped promptly after edge-gluing into sheets of corresponding panel widths, but the curvature of. th issuing web, as manufactured according to my patent above, introduces complications, and makes it dilficult to clip off it the requisite panel widths. The reasons for the stated difficulty in my new process, and the general manner in which the problems so arising have been solved, are set forth more fully in my companion application, Serial No. 160,537, filed May 6, 1950, entitled Process for Preclipping Veneer Sheets to Size. That solution consists essentially of measuring successive individual strip widths until the accumulation of such measurements constitutes a. sheet width,

and then effecting the clipping of an individual strip after it is assembled flatwise in sheet relationship, but before it is bowed or joined therein, along a line such that when eventually its subdivided pieces are edge-glued into the web alon with other such whole strips, the component strips will make up the individual sheet widths preclipped to desired size. So doing avoids the necessity of and the problems involved in at- Claims. CL 214-1) tempting to flatten out a long, continuous web I,

after edge-gluing, and preparatory to clipping to sheet widths, or of attempting to clip a deeply bowed, traveling sheet of indeterminate length. One such problem is the excessive amount of floor space that would be required to first flatten the web, and another is the likelihood of splitting the veneer itself either during the operation of clipping the bowed sheet, or during the process of flattening out the bowed web, particularly if it be attempted to flatten the web other than are set up while it is still in bowed form, and,,.

the bowed unitary sheet is lowered, and in the course of lowering its ends are brought into the same plane as its middle, to complete the flattening of each sheet width immediately following its issuance. The flattening of individual sheets can occur quite abruptly, since by the procedure followed there are no stresses imposed on the veneer in a direction transversely of its grain, hence no tendency to split the veneer. While this flattening constitutes a part of the process that inovlves preclipping, nevertheless the mechanism by which the same is accomplished constitutes the subject matter of this application.

Accordingly it will be seen that it is the object of the present invention to provide mechanism suitable to the reception of wood veneer sheets in bowed condition, capable of displacing them bodily-particularly downwardly-from the path of the following sheet, and operative as a result to bring the ends and the middle of the sheet into approximately planar relationship. Additionally, it is an object of this invention to provide means for removing each flattened sheet so that the sheet-removing means may return to its initial position in time to engage and support the next issuin sheet.

Another object of this invention is to provide mechanism of this nature which shall be substantially automatic in its operation, of simple form, reliable and rugged in use, adjustable for different sizes of sheet, and which occupies but a minimum of floor space.

With these objects in mind, and others as will appear hereinafter (and particularly such as pertain more closely to the mechanical details of the device), the present device comprises the novel mechanism, and the novel combination and arrangement of the parts thereof, in and to each other, and with relation to the preceding platen or sheet guide means, all as is shown in the accompanying drawings, and as will be more particularly described herein and defined in the claims which terminate this specification.

Figure 1 is a general plan view of the mechanism, one sheet being nearly completely discharged from the flattening mechanism, and the following sheet being in process of issuance from the platen or sheet guide.

Figure 2 is a front elevational view of the same mechanism, with elements in substantially the same relative position, and Figure 3 is a cross-sectional view substantially on the line 3-3 of Figure 2, with the first sheet completely discharged, and the following sheet well advanced from the platen.

Figure 4 is an enlarged view, similar to Figure 3 3 but looking in the opposite sense, and Figure 5 is a sectional view on a vertical plane, indicated at 55 in Figure 4.

It has been considered unnecessary to illustrate in the drawings of this application the feeding, clipping, bowing and glue-setting elements of the machine, and for fuller understanding thereof reference is made to my companion application or to the Patent No. 2,544,133. It is sulficient to indicate here that each bowed sheet, composed of several edge-glued strips of thin wood veneer, of a length approximating 100 inches and a width of about 50 inches, issues from a platen section 9 through a curved slot QB, in which platen section it is engaged top and bottom at close intervals by platens 91 and 92, respectively, by means of which a high-frequency discharge is passed through each passing glue line, and serves to heat and set the glue, using the latter term generically. Each sheet PI or F2, made up of individual strips as SI, S2, and S3, or of a remainder R of th strip S3, issues in bowed form from the slot 99, immediately after the edges have been thus joined. There is no particular danger of pulling apart such edges, but if the sheet is unduly or unevenly stressed, particularly along a line transverse to the grain of the wood in the strips, that is to say, transversely to the sheet as a whole, it is not unlikley that the veneer itself will split. It is therefore essential that it be handled gently, even though it issues at the rate of thirty linear feet a minute, and that relief of stresses, when it occurs, shall be substantially simultaneous in all parts of the sheet, and rather abrupt in nature, so that there are no stresses transversely of the width of the sheet, such as might tend to split the'veneer.

In essence, the sole support for the veneer sheet, as it issues from the platen 9, takes the form of a narrow bar I located at about the apex of the bowing of the sheet, midway between the sheets ends, and just beneath its lower surface. Such a bar, so located, approximately balances, supports, .and maintains the bowing of the sheet without introducing any such lateral stresses as are undesirable, and such support is afforded until the sheet is clear of the platen. It will be understood that the sheet is thus pushed clear by the sheet, as P3 in Figure 3, which follows behind it, and which is advanced positively, as by the feed rollers 95.

The bar I is supported upon a rod or plunger Iii, which is received in a cylinder II, which normally would be sunk beneath the floor level. The operation is preferably pneumatic, since speed of operation is very desirable, and the operation occurs in such manner that when a sheet has been fully received upon the bar I, the bar is automatically lowered promptly, to displace the sheet bodily from the path of the following sheet, as P2. Such operation may readily be accomplished by employing a trip mechanism, including the trigger 2 alongside the bar I in the path of the advancing edge of a sheet, to be engaged by the latter, and when so engaged to effect operation of a switch 26, and through a circuit 2| to operate a solenoidcontrolled valve 22 for the supply of air by way of the conduit 23 to the cylinder I I. The cylinder is of the type which automatically completes a reciprocation, down and then up immediately, stopping at its initial position.

This downward movement of the bar I, with the sheet supported thereon and drooping at '4 its ends, and the resultant downward movement of th sheet, causes some compression of the air beneath it, and this constitutes an air cushion that tends to lift the descending ends of the sheet, with the result that when the sheet drops upon rollers 3, which are at some considerable distance below the level of issuance of the sheet, the sheet has been largely flattened out by the air cushion effect, and is lowered quite gently upon the rollers 3. These rollers being preferably live rollers, operating in conjunction with a pressure roll 30, the whole driven continuously from a motor 3|, act to whisk the sheet away from its position above the bar and beneath the following sheet P2, in the manner in which it is shown operating upon the sheet PI in Figure 1. Obviously fair leads, such as are shown at 32, will prevent engagement of the sheets leading end edge with any of the rollers, and will guide this edge upwardly and over the rollers 3 on its Way out. Immediately the sheet has moved away from the location of the bar I, the bar moves back upwardly and arrives in time to afford the necessary support to the following sheet P2. The ofirunning sheet PI is discharged upon a stack, shown at P4, and this, too, may be upon an elevator E, by means of which a number of such sheets may be stacked for subsequent handling. Any such stacking means is subsidiary or complemental, only, to the principal features of this invention.

Were the sheet to be left wholly free from restraint, as it comes to rest upon the bar I, it might teeter thereon or slip therefrom, or otherwise prove difiicult to control. Accordingly I provide means to bow the sheet slightly more as it issues, thereby merely to retain control of it, and such means are shown in the form of rods 4 and shields 4U, fixedly positioned above the issuing sheet, the function of which is to engage and to urge further downwardly the drooping ends of sheet P2 in Figures 2 and 5, and to bow the sheet slightly farther about the bar I than the ends would normally droop. This furnishes enough restraint to prevent premature toppling of the sheet. As soon as the bar I begins to lower away from the overhead rods 4 and shields 40, these fixed restraining elements relinquish their hold on the sheet and their control thereover, and the flattening of the sheet under the influence f the air cushion begins, in the manner indicated in the dash lines in Figure 5. The flattening of the sheet is completed, as shown in that figure in dot-dash lines, and it is shown in that figure in full lines in process of being discharged endwise by the rollers 3 and 30.

Other details of the mechanism are of minor importance, there being guides at I5 for an end of the bar I, and a surrounding framework 6 that constitutes, in effect, a bin or receptacle into which the sheet is discharged, and by which it is prevented from flying out of control. The position of the trip element 2 is adjustable lengthwise of the bar I, and the device as a whole is of such size and dimensions, as will permit it to receive different sizes of sheets, from the maximum for which the splicing mechanism is designed down to a minimum size.

The operation of the device should now be selfevident, but in brief, each composite preclipped sheet Pl, P2, or P3 emerges in bowed form from the slot 90, and slides along the upraised bar I, its sole support. 'Its ends droop as soon as it has emerged, but the overlying rods 4 and shields 40 bow it somewhat farther downwardly, over the centralized bar, and so prevent its toppling off that bar. As soon as a given panel has fully emerged, under the urging of a following panel that pushes it through, the issued panels leading edge strikes the trigger 2, and the bar I drops from beneath the issued panel. The rods 4 and shield 40 are wholly above the panel, so they now furnish it no further support; the panel drops, and in dropping flattens out, and the air cushion beneath it lets it down without undue impact, upon the live rolls 3. The bar 4 is at this time below the level defined by these rolls 3, hence the panel is whisked endwise by the rolls, without interference by the bar, onto the stack P4 on the elevator E. As soon as the dropped panel clears the bar I, the latter starts upwardly to its original position, arriving in time to engage beneath and to support the next-issuing panel before the latter has emerged very far. There is nothing except preset sequence means in the bars actuating mechanism to initiate upward movement of the bar I, but it has been found possible to start it back upwardly while the dropped panel is still moving endwise upon the rolls 3, just after its end clears the lowered bar I.

It is to be understood that this mechanism operates upon flexible wood veneer sheets, and not upon laminated plywood panels, for the latter are not sufficiently flexible to be bowed, as described above, nor, for that matter, is there any particular need to handle plywood panels thus gently and carefully, even if it Were possible to do so.

I claim as my invention:

1. In combination with a sheet guide means, for supporting individual veneer sheets each of which has just been formed by edge-gluing edgeabutted strips while the latter are bowed upwardly from a horizontal plane in the direction of their grain and their length, during their edgewise advance, so bowed, in the direction transverse to the length of such strips and the composite sheets, to a discharge point, a sheet unloader which comprises a bar at such discharge point aligned with and slightly below the apex of the issuing sheets bow, to support the sheet in its bowed form during and after issuance, means to lower said bar upon completion of issuance of a sheet, and means to support the ends of the sheet, the middle whereof is descending, and thereby to bring the sheet into approximately planar, horizontal disposition, at a location below its place of issuance.

2. The combination of claim 1, including means operable upon the so-flattened sheet to discharge the same edgewise.

3. The combination of claim 1, including trip mechanism to effect energization of the lowering means, located in the path of the issuing sheet for engagement by the latter upon its complete issuance, for automatic actuation thereby of the lowering means.

4. The combination of claim 1, wherein the end-supporting means are located materially below the location of the issuing ends, whereby the air beneath such ends, as they descend, initiates and cushions leveling movement of the ends.

5. The combination of claim 1, including members disposed towards the ends of the sheet, outwardly from the bar, in such position and so formed as to engage the sheets upper surfaces and to press further downwardly the ends of the sheet as it issues from the guide means and is sup-ported upon the central bar.

6. The combination of claim 1, including means to limit continued movement of the sheet after issuance, live rollers spaced beneath the issued sheet, and constituting part of the end-supporting means, and active to discharge the flattened sheet edgewise, trip mechanism alongside the bar, in position to be engaged and actuated by the issued sheet, and an operative connection between said trip mechanism and the bar-lowering means, to lower the same automatically following issuance of a sheet, for deposit of the sheet upon the discharge rollers, and automatically to raise the bar for engagement beneath the following sheet.

7. In combination with guide means for successive flexible sheets each of appreciable stiffness and area, which guide means is curved downwardly at each end from a central high point, means to push the sheets in succession edgewise beyond said guide means, each in longitudinally curved form, drooping at its ends, a narrow bar oriented in the direction of movement of the sheet and located, during emergence of each sheet, closely beneath the sheets central high point, constituting the sole support for such sheet upon its emergence, sheet-receiving means vertically beneath the sheet while thus supported, defining a substantially planar support for the sheet, and means to displace said bar from beneath the sheet, leaving the sheet free to drop upon said planar support, and to return said bar to sheetsupporting position in time to receive and support the next-issuing sheet.

8. The combination of claim 7, including restraining elements fixed in position to overlie the sheet as it issues from the sheet guide means, at each side of the central bar, and in cooperation with the latter to maintain the sheets curvature approximately unchanged during and immediately following its issuance, but being disengaged by the dropping sheet upon withdrawal of the bar.

9. The mechanism defined in claim 7, wherein the sheet-receiving means include live rolls, defining the planar support, and operative to discharge each sheet edgewise from beneath the next-issuing sheet, and characterized in the inclusion of means guiding the bar, upon its displacement, downwardly to a level beneath the planar support defined by said rolls.

10. The mechanism defined in claim 7, including also a trigger device operatively connected to said bar-displacing means to initiate operation of the latter, said trigger device being located for operative engagement by each panel as the same completes its emergence from the sheet guide means.

ARTHUR C. CARLSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,685,799 Baker Oct. 2, 1928 1,706,533 Lorig et a1 Mar. 26, 1929 2,177,941 Knudson et a1 Oct. 31, 1939 2,472,225 Muddiman June 7, 1949 2,548,767 Brest Apr. 10, 1951 

